Power Sequencing for Optimal System Load at Start Up

1. A method for power sequencing in a chassis configurable to receive a plurality of blades, comprising: determining a chassis configuration prior to the plurality of blades disposed within a respective plurality of slots of the chassis being powered up; generating a power sequence based on the determining; applying the power sequence to the blades; monitoring the applying and the chassis configuration, the monitoring including detecting a difference between an actual system load and an expected system load; and adjusting the power sequence for a next power cycle to converge to the expected system load.

2. The method of claim 1 , wherein the determining includes determining a time interval based on blade attributes.

3. The method of claim 1 , wherein the determining includes identifying blade attributes, the blade attributes associated with physical characteristics and electrical characteristics of a corresponding blade.

4. The method of claim 1 , wherein the monitoring includes detecting a change to the chassis configuration; and adjusting the power sequence for a next power cycle to maintain the expected system load.

5. The method of claim 1 , further comprising: detecting a chassis identifier of each of a plurality of chassis, including the chassis, in a rack; determining a further sequence with which to apply power, one or more chassis at a time, to the plurality of chassis, based on the chassis identifier of each of the plurality of chassis; and applying power to the plurality of chassis in accordance with the further sequence and the chassis identifier of each of the plurality of chassis.

6. The method of claim 1 , wherein generating the power sequence is based on a policy specifying a maximum number of the blades starting contemporaneously.

7. A power sequencing system, comprising: a chassis having a plurality of slots configurable to accept a respective plurality of blades; each blade of the plurality of blades having blade attributes that circuitry within the chassis is configured to identify prior to applying power to the plurality of blades; and the circuitry within the chassis configured to apply a power sequencing method to the plurality of blades, the method comprising: generating a power sequence based on the identified blade attributes and a chassis configuration; applying the power sequence to the plurality of blades; monitoring the applying and the chassis configuration, the monitoring including detecting a difference between an actual system load and an expected system load; and adjusting the power sequence for a next power cycle to converge to the expected system load.

8. The power sequencing system of claim 7 , wherein the circuitry within the chassis includes at least one of: a coupling to ground, or one or more resistors, wherein the coupling to ground or a value of the one or more resistors indicates a slot of the chassis as being occupied by a blade.

9. The power sequencing system of claim 7 , further comprising: a timer configured to produce time intervals based on the blade attributes of each of the plurality of blades, wherein the power sequence is based on the time intervals.

10. The power sequencing system of claim 7 , further comprising: each of the plurality of slots of the chassis having a default resistor value; and each of the plurality of blades having a further resistor value, detectable by the circuitry within the chassis, wherein the further resistor value is lower than the default resistor value.

11. The power sequencing system of claim 7 , further comprising: each of the plurality of slots of the chassis having a timing circuit with a timer and a capacitor; and each of the plurality of blades having a resistor, a value of which is associated with the blade attributes, wherein the sequence is based on a time constant of the capacitor and the resistor, for each of the plurality of blades.

12. The power sequencing system of claim 7 , further comprising: a plurality of chassis, including the chassis; a rack; each chassis of the plurality of chassis having a chassis identifier; and circuitry of the rack configured to apply power in a further sequence to successive chassis of the plurality of chassis, with the further sequence determined in accordance with the chassis identifier of each chassis.

13. The power sequencing system of claim 7 , further comprising: each blade of the plurality of blades configurable to determine whether the blade is a first blade to power up in the power sequence and designate the first blade as a master node.

14. A power sequencing chassis, comprising: a chassis having a plurality of slots, wherein the plurality of slots are configurable to receive a respective plurality of blades; circuitry of the chassis configurable to execute a power sequence method for powering each blade of the plurality of blades, the method comprising: determining a chassis configuration prior to the plurality of blades being powered up within the plurality of slots of the chassis; generating a power sequence based on the determining; applying the power sequence to the plurality of blades; monitoring the applying and the chassis configuration; and for each blade of the plurality of blades determining whether the blade is a first blade to power up in the power sequence and if so designate the first blade as a master node.

15. The power sequencing chassis of claim 14 , further comprising: each of the plurality of blades having a selectable resistance that can be set to a resistance value to represent blade attributes, the blade attributes associated with physical characteristics and electrical characteristics of a corresponding blade.

16. The power sequencing chassis of claim 14 , further comprising: the circuitry of the chassis including a timer and a capacitor that cooperate with a resistor of each blade of the plurality of blades to produce a time interval specific to the blade, wherein the power sequence is based on the time interval produced for each of the plurality of blades.

17. The power sequencing chassis of claim 14 , further comprising: a rack having a timer and a capacitor that cooperate with a resistor of each of a plurality of chassis, including the chassis, to produce a time interval specific to the chassis; and circuitry of the rack configured to power up successive chassis, of the plurality of chassis, one or more chassis at a time, in a further sequence based on the time interval of each of the plurality of chassis.

18. The power sequencing chassis of claim 14 , further comprising: the circuitry of the chassis configured to generate a vector based on which of the plurality of slots is occupied by one of the plurality of blades, wherein the power sequence is based on the vector and wherein the power sequence changes when a further blade is inserted to the chassis.

19. The power sequencing chassis of claim 14 , wherein the circuitry of the chassis generating the power sequence includes a linear feedback shift register and does not include a processor.

20. The power sequencing chassis of claim 14 , wherein the method for the circuitry of the chassis further comprises: detecting a difference between an actual system load and an expected system load during the monitoring; and adjusting the power sequence for a next power cycle to converge to the expected system load.